You may have already noticed Mars after dark in recent weeks, looking like a bright star wearing a lot of rouge. It's been working its way toward the closest it's been to Earth in about 15 years.

It'll technically reach that point July 31, but on Friday will be at "opposition," appearing directly opposite the sun from our cosmic vantage point. As a result, the Red Planet will rise at sunset and stay in the sky until sunrise.

The moon will also take on a reddish-orange look Friday night for longer than at any time in the next century.

This is thanks to the longest total lunar eclipse of the 21st century, which is set to go down July 27. In fact, it's probably the longest such event between now and 2123, according to NASA's catalog of such things.

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The planets are aligned for a lunar eclipse, blood moon...

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A total lunar eclipse occurs when the sun, earth and moon are in a line, casting the reddish-orange shadow of our planet onto the surface of the moon. This is why a total lunar eclipse is often referred to as a "blood moon."

The scientific explanation for the creepy, red-tinted satellite is admittedly a little less exciting than the more hysterical explanation from ancient times: that some kind of huge, unseen dragon in the sky is going to attempt to devour the moon but ultimately fail.

Whatever your favored explanation, it's happening this month and it'll last for a whopping 1 hour and 43 minutes. But there's a catch: It'll be visible only in parts of South America, Africa, the Middle East and Asia. The map below from NASA provides an idea of where to plan your travel for the best blood moon viewing.